Tapped Inductor Cell Balancing for Low-Loss Battery Packs
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Solution Overview
Problem
Existing battery balancing systems are inefficient, particularly for larger batteries, as they often dissipate energy through resistive loads or require multiple chargers, limiting the utility and efficiency of battery packs.
Innovation Solution
A serial tapped inductor battery balancing system that uses a chain of inductors and switches to manage current flow between cells, allowing for non-dissipative balancing by adjusting the state of charge across cells through alpha and beta switches controlled by a controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If resistive balancing is used to balance battery cells, then the balancing function is achieved, but energy is wasted and heat is generated
Solution Approach 1:
The patent introduces an inductor as an intermediary energy storage component between battery cells. The inductor temporarily stores energy from higher-voltage cells during charging and releases it to lower-voltage cells, enabling balancing without direct resistive dissipation. This mediator approach transfers energy constructively rather than wasting it as heat.
Solution Approach 2:
The patent changes the balancing parameter from direct voltage equalization through resistance to current-controlled charge transfer through inductors. By controlling the switching timing and duration of charge/discharge cycles through the inductor, the system achieves balancing while maintaining energy efficiency and reducing thermal effects.
2Measurement precision
If multiple chargers are used to balance larger batteries, then balancing accuracy is improved, but system complexity and cost increase
Solution Approach 1:
The patent creates a universal balancing circuit that can balance any number of series-connected battery cells using a single inductor and switch array. The same basic circuit topology scales to accommodate different battery pack sizes by simply activating different switch combinations, eliminating the need for multiple dedicated chargers or complex modular balancing systems.
Solution Approach 2:
The patent merges multiple balancing functions into a single integrated circuit. Instead of using separate chargers or balancing modules for each cell or cell group, the system combines all balancing operations into one unified inductor-based circuit controlled by a centralized switch array, reducing overall system complexity while maintaining balancing capability.
3Quantity of substance
If top balancing is used to charge all cells to 100%, then maximum charge capacity is achieved, but cells become unbalanced during discharge
Solution Approach 1:
The patent implements continuous balancing action during both charging and discharging phases. The inductor-based circuit continuously monitors and adjusts charge distribution among cells throughout the entire charge-discharge cycle, rather than only at the top or bottom of the cycle. This continuous intervention maintains balance stability while preserving maximum charge capacity.
Solution Approach 2:
The patent employs periodic switching of the inductor charge/discharge cycles to maintain cell balance. The controller periodically activates the inductor to transfer charge between cells based on their instantaneous voltage differences, creating a rhythmic balancing action that continuously corrects imbalances during both charging and discharging operations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach maximizes energy availability by balancing cells without energy loss, reducing costs, and maintaining efficiency across various charging stages, making larger batteries more effective and cost-efficient.
Implementation Method 1
a first inductor, the second inductor may be both in electrical connection with the second switch and a third inductor
Data Source
AI summary
A battery balancing device may comprise: a positive terminal of a power source connected to a first cell and an alpha switch; a second cell and a first switch both in connection with a negative terminal of the first cell; and a third cell and a second switch both in electrical connection with the negative terminal of the second cell. The alpha switch may be in series with a first inductor, the first inductor may be both in electrical connection with the first switch and a second inductor, the second inductor may be both in electrical connection with the second switch and a third inductor; the third inductor may be in series with a beta switch; and the beta switch and the third cell may both be in electrical connection with a negative terminal of the power source. Moreover, a method for balancing a string of battery cells is provided.